非充分采动下浅埋坚硬顶板“两带”高度分析

Analysis on height of “two zones” under subcritical mining in shallow coal seam with hard roof

为研究非充分采动下浅埋坚硬顶板"两带"高度,防止工作面开采过程中出现溃水、溃砂等安全事故,结合赵屋煤矿地质采矿条件,采用地表钻孔冲洗液漏失量现场观测及数值模拟,对赵屋煤矿采空区上覆岩层"两带"高度进行了研究,揭示了非充分采动下浅埋深坚硬顶板"两带"高度及其变化规律。研究结果表明:非充分采动下浅埋深坚硬顶板"两带"高度低于充分采动,采宽26 m时裂采比为7.65;导水裂隙带的高度整体呈阶梯型变化,一个阶段到下一个阶段都以突跳方式进入;非充分采动条件下,"三下采煤规程"中"两带"计算公式及传统经验值18~28倍裂采比在应用时需考虑采动的充分性。

In order to study the height of ＂two zones＂ under the subcritical mining in the shallow coal seam with hard roof and to prevent the water and sand inrushing to the working face, the height of＂two zones＂ is studied using the comprehensive theoretical analysis, numerical simulations and observations of surface borehole flushing fluid loss based on the geological and mining conditions of Zhaowu coal mine. The results show that the height of ＂two zones＂ under the subcritical mining is lower than that under the supercritical mining, the ratio of fracture is 7.65 when the mining width is 26m. The height of water flowing fractured zone shows a step change. One stage just jump into the next stage. Under the conditions of subcritical mining, it is necessary to consider the supercritical mining when applying the formula of height of ＂two zones＂ with following the ＂coal mining regulations＂ and the empirical value of 18~28 times of the ratio of fracture.